Package it.unimi.dsi.fastutil.doubles

Class DoubleIterators

java.lang.Object
it.unimi.dsi.fastutil.doubles.DoubleIterators
public final class DoubleIterators extends Object
A class providing static methods and objects that do useful things with type-specific iterators.
See Also:

  • Field Details

    • EMPTY_ITERATOR

      public static final DoubleIterators.EmptyIterator EMPTY_ITERATOR
      An empty iterator. It is serializable and cloneable.

      The class of this objects represent an abstract empty iterator that can iterate as a type-specific (list) iterator.

  • Method Details

    • singleton

      public static DoubleListIterator singleton(double element)
      Returns an immutable iterator that iterates just over the given element.
      Parameters:
      element - the only element to be returned by a type-specific list iterator.
      Returns:
      an immutable iterator that iterates just over element.

    • wrap

      public static DoubleListIterator wrap(double[] array, int offset, int length)
      Wraps the given part of an array into a type-specific list iterator.

      The type-specific list iterator returned by this method will iterate length times, returning consecutive elements of the given array starting from the one with index offset.

      Parameters:
      array - an array to wrap into a type-specific list iterator.
      offset - the first element of the array to be returned.
      length - the number of elements to return.
      Returns:
      an iterator that will return length elements of array starting at position offset.

    • wrap

      public static DoubleListIterator wrap(double[] array)
      Wraps the given array into a type-specific list iterator.

      The type-specific list iterator returned by this method will return all elements of the given array.

      Parameters:
      array - an array to wrap into a type-specific list iterator.
      Returns:
      an iterator that will return the elements of array.

    • unwrap

      public static int unwrap(DoubleIterator i, double[] array, int offset, int max)
      Unwraps an iterator into an array starting at a given offset for a given number of elements.

      This method iterates over the given type-specific iterator and stores the elements returned, up to a maximum of length, in the given array starting at offset. The number of actually unwrapped elements is returned (it may be less than max if the iterator emits less than max elements).

      Parameters:
      i - a type-specific iterator.
      array - an array to contain the output of the iterator.
      offset - the first element of the array to be returned.
      max - the maximum number of elements to unwrap.
      Returns:
      the number of elements unwrapped.

    • unwrap

      public static int unwrap(DoubleIterator i, double[] array)
      Unwraps an iterator into an array.

      This method iterates over the given type-specific iterator and stores the elements returned in the given array. The iteration will stop when the iterator has no more elements or when the end of the array has been reached.

      Parameters:
      i - a type-specific iterator.
      array - an array to contain the output of the iterator.
      Returns:
      the number of elements unwrapped.

    • unwrap

      public static double[] unwrap(DoubleIterator i, int max)
      Unwraps an iterator, returning an array, with a limit on the number of elements.

      This method iterates over the given type-specific iterator and returns an array containing the elements returned by the iterator. At most max elements will be returned.

      Parameters:
      i - a type-specific iterator.
      max - the maximum number of elements to be unwrapped.
      Returns:
      an array containing the elements returned by the iterator (at most max).

    • unwrap

      public static double[] unwrap(DoubleIterator i)
      Unwraps an iterator, returning an array.

      This method iterates over the given type-specific iterator and returns an array containing the elements returned by the iterator.

      Parameters:
      i - a type-specific iterator.
      Returns:
      an array containing the elements returned by the iterator.

    • unwrap

      public static long unwrap(DoubleIterator i, double[][] array, long offset, long max)
      Unwraps an iterator into a big array starting at a given offset for a given number of elements.

      This method iterates over the given type-specific iterator and stores the elements returned, up to a maximum of length, in the given big array starting at offset. The number of actually unwrapped elements is returned (it may be less than max if the iterator emits less than max elements).

      Parameters:
      i - a type-specific iterator.
      array - a big array to contain the output of the iterator.
      offset - the first element of the array to be returned.
      max - the maximum number of elements to unwrap.
      Returns:
      the number of elements unwrapped.

    • unwrap

      public static long unwrap(DoubleIterator i, double[][] array)
      Unwraps an iterator into a big array.

      This method iterates over the given type-specific iterator and stores the elements returned in the given big array. The iteration will stop when the iterator has no more elements or when the end of the array has been reached.

      Parameters:
      i - a type-specific iterator.
      array - a big array to contain the output of the iterator.
      Returns:
      the number of elements unwrapped.

    • unwrap

      public static int unwrap(DoubleIterator i, DoubleCollection c, int max)
      Unwraps an iterator into a type-specific collection, with a limit on the number of elements.

      This method iterates over the given type-specific iterator and stores the elements returned, up to a maximum of max, in the given type-specific collection. The number of actually unwrapped elements is returned (it may be less than max if the iterator emits less than max elements).

      Parameters:
      i - a type-specific iterator.
      c - a type-specific collection array to contain the output of the iterator.
      max - the maximum number of elements to unwrap.
      Returns:
      the number of elements unwrapped. Note that this is the number of elements returned by the iterator, which is not necessarily the number of elements that have been added to the collection (because of duplicates).

    • unwrapBig

      public static double[][] unwrapBig(DoubleIterator i, long max)
      Unwraps an iterator, returning a big array, with a limit on the number of elements.

      This method iterates over the given type-specific iterator and returns a big array containing the elements returned by the iterator. At most max elements will be returned.

      Parameters:
      i - a type-specific iterator.
      max - the maximum number of elements to be unwrapped.
      Returns:
      a big array containing the elements returned by the iterator (at most max).

    • unwrapBig

      public static double[][] unwrapBig(DoubleIterator i)
      Unwraps an iterator, returning a big array.

      This method iterates over the given type-specific iterator and returns a big array containing the elements returned by the iterator.

      Parameters:
      i - a type-specific iterator.
      Returns:
      a big array containing the elements returned by the iterator.

    • unwrap

      public static long unwrap(DoubleIterator i, DoubleCollection c)
      Unwraps an iterator into a type-specific collection.

      This method iterates over the given type-specific iterator and stores the elements returned in the given type-specific collection. The returned count on the number unwrapped elements is a long, so that it will work also with very large collections.

      Parameters:
      i - a type-specific iterator.
      c - a type-specific collection to contain the output of the iterator.
      Returns:
      the number of elements unwrapped. Note that this is the number of elements returned by the iterator, which is not necessarily the number of elements that have been added to the collection (because of duplicates).

    • pour

      public static int pour(DoubleIterator i, DoubleCollection s, int max)
      Pours an iterator into a type-specific collection, with a limit on the number of elements.

      This method iterates over the given type-specific iterator and adds the returned elements to the given collection (up to max).

      Parameters:
      i - a type-specific iterator.
      s - a type-specific collection.
      max - the maximum number of elements to be poured.
      Returns:
      the number of elements poured. Note that this is the number of elements returned by the iterator, which is not necessarily the number of elements that have been added to the collection (because of duplicates).

    • pour

      public static int pour(DoubleIterator i, DoubleCollection s)
      Pours an iterator into a type-specific collection.

      This method iterates over the given type-specific iterator and adds the returned elements to the given collection.

      Parameters:
      i - a type-specific iterator.
      s - a type-specific collection.
      Returns:
      the number of elements poured. Note that this is the number of elements returned by the iterator, which is not necessarily the number of elements that have been added to the collection (because of duplicates).

    • pour

      public static DoubleList pour(DoubleIterator i, int max)
      Pours an iterator, returning a type-specific list, with a limit on the number of elements.

      This method iterates over the given type-specific iterator and returns a type-specific list containing the returned elements (up to max). Iteration on the returned list is guaranteed to produce the elements in the same order in which they appeared in the iterator.

      Parameters:
      i - a type-specific iterator.
      max - the maximum number of elements to be poured.
      Returns:
      a type-specific list containing the returned elements, up to max.

    • pour

      public static DoubleList pour(DoubleIterator i)
      Pours an iterator, returning a type-specific list.

      This method iterates over the given type-specific iterator and returns a list containing the returned elements. Iteration on the returned list is guaranteed to produce the elements in the same order in which they appeared in the iterator.

      Parameters:
      i - a type-specific iterator.
      Returns:
      a type-specific list containing the returned elements.

    • asDoubleIterator

      public static DoubleIterator asDoubleIterator(Iterator i)
      Wraps a standard iterator into a type-specific iterator.

      This method wraps a standard iterator into a type-specific one which will handle the type conversions for you. Of course, any attempt to wrap an iterator returning the instances of the wrong class will generate a ClassCastException. The returned iterator is backed by i: changes to one of the iterators will affect the other, too.

      Parameters:
      i - an iterator.
      Returns:
      a type-specific iterator backed by i.
      Implementation Notes:
      If i is already type-specific, it will returned and no new object will be generated.

    • asDoubleIterator

      public static DoubleListIterator asDoubleIterator(ListIterator i)
      Wraps a standard list iterator into a type-specific list iterator.

      This method wraps a standard list iterator into a type-specific one which will handle the type conversions for you. Of course, any attempt to wrap an iterator returning the instances of the wrong class will generate a ClassCastException. The returned iterator is backed by i: changes to one of the iterators will affect the other, too.

      If i is already type-specific, it will returned and no new object will be generated.

      Parameters:
      i - a list iterator.
      Returns:
      a type-specific list iterator backed by i.

    • any

      public static boolean any(DoubleIterator iterator, DoublePredicate predicate)
      Returns whether an element returned by the given iterator satisfies the given predicate.

      Short circuit evaluation is performed; the first true from the predicate terminates the loop.

      Returns:
      true if an element returned by iterator satisfies predicate.

    • all

      public static boolean all(DoubleIterator iterator, DoublePredicate predicate)
      Returns whether all elements returned by the given iterator satisfy the given predicate.

      Short circuit evaluation is performed; the first false from the predicate terminates the loop.

      Returns:
      true if all elements returned by iterator satisfy predicate.

    • indexOf

      public static int indexOf(DoubleIterator iterator, DoublePredicate predicate)
      Returns the index of the first element returned by the given iterator that satisfies the given predicate, or −1 if no such element was found.

      The next element returned by the iterator always considered element 0, even for ListIterators. In other words ListIterator.nextIndex is ignored.

      Returns:
      the index of the first element returned by iterator that satisfies predicate, or −1 if no such element was found.

    • concat

      public static DoubleIterator concat(DoubleIterator... a)
      Concatenates all iterators contained in an array.

      This method returns an iterator that will enumerate in order the elements returned by all iterators contained in the given array.

      Parameters:
      a - an array of iterators.
      Returns:
      an iterator obtained by concatenation.

    • concat

      public static DoubleIterator concat(DoubleIterator[] a, int offset, int length)
      Concatenates a sequence of iterators contained in an array.

      This method returns an iterator that will enumerate in order the elements returned by a[offset], then those returned by a[offset + 1], and so on up to a[offset + length - 1].

      Parameters:
      a - an array of iterators.
      offset - the index of the first iterator to concatenate.
      length - the number of iterators to concatenate.
      Returns:
      an iterator obtained by concatenation of length elements of a starting at offset.

    • unmodifiable

      public static DoubleIterator unmodifiable(DoubleIterator i)
      Returns an unmodifiable iterator backed by the specified iterator.
      Parameters:
      i - the iterator to be wrapped in an unmodifiable iterator.
      Returns:
      an unmodifiable view of the specified iterator.

    • unmodifiable

      public static DoubleBidirectionalIterator unmodifiable(DoubleBidirectionalIterator i)
      Returns an unmodifiable bidirectional iterator backed by the specified bidirectional iterator.
      Parameters:
      i - the bidirectional iterator to be wrapped in an unmodifiable bidirectional iterator.
      Returns:
      an unmodifiable view of the specified bidirectional iterator.

    • unmodifiable

      public static DoubleListIterator unmodifiable(DoubleListIterator i)
      Returns an unmodifiable list iterator backed by the specified list iterator.
      Parameters:
      i - the list iterator to be wrapped in an unmodifiable list iterator.
      Returns:
      an unmodifiable view of the specified list iterator.

    • wrap

      public static DoubleIterator wrap(ByteIterator iterator)
      Returns an iterator backed by the specified byte iterator.
      Parameters:
      iterator - a byte iterator.
      Returns:
      an iterator backed by the specified byte iterator.

    • wrap

      public static DoubleIterator wrap(ShortIterator iterator)
      Returns an iterator backed by the specified short iterator.
      Parameters:
      iterator - a short iterator.
      Returns:
      an iterator backed by the specified short iterator.

    • wrap

      public static DoubleIterator wrap(CharIterator iterator)
      Returns an iterator backed by the specified char iterator.

      WARNING: This is not the same as converting the source to a sequence of code points. This returned instance literally performs (int)(charValue) casts. Surrogate pairs will be left as separate elements instead of combined into a single element with the code point it represents. See Character for more discussion on code points, char values, and surrogate pairs.

      Parameters:
      iterator - a char iterator.
      Returns:
      an iterator backed by the specified char iterator.

    • wrap

      public static DoubleIterator wrap(IntIterator iterator)
      Returns an iterator backed by the specified integer iterator.
      Parameters:
      iterator - an integer iterator.
      Returns:
      an iterator backed by the specified integer iterator.

    • wrap

      public static DoubleIterator wrap(FloatIterator iterator)
      Returns an iterator backed by the specified float iterator.
      Parameters:
      iterator - a float iterator.
      Returns:
      an iterator backed by the specified float iterator.